In various surgical procedures, it is necessary to dissect bone or other tissue. Many conventional surgical instruments used for the dissection of bone or other tissue employ pneumatic or electrical motors to rotate a cutting element. In their most basic form, such surgical instruments comprise a motor portion having a rotary shaft, a dissection tool having a cutting or abrading element that is moved by the rotating shaft of the motor, and a coupling arrangement for connecting the dissection tool to a spindle or collet of the rotary shaft. The spindle or collet of the rotary shaft is usually housed within a base that is attached to the motor.
Because it is frequently necessary to replace the dissection tool, it is also known in the art to use a quick release coupling to secure the dissection tool to the surgical instrument. An example of such a quick release coupling is shown and described in commonly assigned U.S. Pat. No. 5,505,737 entitled “Quick Release Coupling For A Dissecting Tool” incorporated herein by reference. The coupling device shown in U.S. Pat. No. 5,505,737 includes a spindle attachment which is secured to a spindle of a surgical instrument. The spindle attachment has a shaft engagement portion for engaging a shaft of the dissection tool. The shaft engagement portion of the spindle attachment is provided with apertures that terminate within a central bore of the engagement portion through which the shaft of the dissection tool extends.
Powered surgical dissection instruments often utilize dissection tools having small shaft diameters in relation to their length. Such shafts may bend or flail in use if not adequately supported. This occurrence may be heightened when such shafts are used with motors that are designed to reach speeds in excess of 72,000 rpm. Tool makers have provided attachments or tubes that engages the motor portion and receive a portion of the dissection tool shaft. Typically, such an attachment will include one or more bearing that support the dissection tool shaft at it extends from the tool collet. Attachments may be provided with many configurations varying by length, diameter and function. While telescoping attachments have been utilized which provide the capability of varying the distance the distal tip of the tube extends from the motor housing, the installation and adjustment of such devices remains cumbersome.
While known surgical tools include adjustable components, a need exists in the pertinent art for an improved surgical tool which permits telescoping of the attachment relative to the motor.